Building a new Royal Yacht Britannia has “overwhelming support” and would allow the Conservatives finally to deliver on a 20 year old Conservative manifesto pledge, the party’s official historian Lord Lexden says.

In a letter to today's Daily Telegraph, Lord Lexden said a new yacht would fulfil a “deep longing” for Britain to show that it is “confident about our capacity to shape a new national destiny” outside the EU.

He says: “It is hard to think of anything that would hearten our country more than the revival of our neglected maritime traditions which a new royal yacht would symbolise.”

More than 70 Conservative MPs are backing plans for a new royal yacht to act as a catalyst for a newly independent Britain to win new trade deals.

Lord Lexden points out that John Major’s Government first scrapped a replacement for Britannia in 1995 before announcing that it would go ahead after all 20 years ago this month, in January 1997.

However Labour’s Prime Minister Tony Blair then axed plans for the new yacht in October 1997.

Lord Lexden says: “History and tradition meant nothing to New Labour, and Tony Blair scrapped the plans. Is this not a fitting moment for Mrs May to redeem that firm twenty-year old Tory pledge?

“Surely we have not declined so far in the intervening period that public funds are inadequate to meet the cost?

“There is overwhelming support for the original plan of making a new yacht a gift from us all to a beloved sovereign.

“Brexit makes an initiative by Mrs May even more appropriate. There is at the moment a deep longing for decisive practical action which shows that we are confident about our capacity to shape a new national destiny.

“It is hard to think of anything that would hearten our country more than the revival of our neglected maritime traditions which a new royal yacht would symbolise.”

The peer’s comments were welcomed by Jake Berry, the Conservative MP who is leading the Parliamentary campaign for the yacht.

He said: “The year 2017 must be the year we make a new Britannia a reality. The Commonwealth and nations separate from the continent of Europe should be the focus for the new Global Britain.

“A new Britannia uses the waters between us as a natural highway to promote trade and the soft power and influence of Britain abroad.”